Method for preparing cadmium sulfide film

Abstract

A method for preparing a cadmium sulfide film comprises: providing a slurry; coating a first substrate with the slurry; heating the first substrate to produce a vapor; and depositing the vapor on a second substrate to form a cadmium sulfide film. The slurry comprises a dispersant, cadmium particles and sulfur particles.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Chinese Patent Application No. 200910105671.3, filed Feb. 27, 2009, the entire contents of which are incorporated herein by reference.FIELD[0002]The present disclosure relates to a method for preparing a cadmium sulfide film.BACKGROUND[0003]Cadmium sulfide is a wide band gap semiconductor material with stable chemical performance. It can be used in solar cells, where the cadmium sulfide functions as an n-type semiconductor layer and absorbing layer. For example, it can form a p-n junction together with a p-type layer such as Cu(InGa)Se, CdTe and so on, and further can form a solar cell. In these cells, light transmitting through a cadmium sulfide layer is further absorbed by p type semiconductor near the p-n injunction. The performance of the cadmium sulfide layer directly affects the performance of the absorbing film prepared thereof. Therefore, cadmium sulfide is very important for the efficiency and ...

AI Technical Summary

Benefits of technology

[0007]Moreover, when preparing a cadmium sulfide film using the conventional CSS method, the utilization rate of the material is low, generally around 10%. In the CSS method, cadmium sulfide particles are placed into a crucible. After the crucible is covered, it may be difficult to add the exact amount of the source material into the crucible. The source material may be repeatedly used. In the repeatedly using process, the particle size, the particles density, and the chemical stoichiometry may change in the sublimation process and they may become difficult to control. With the repeated formation of the film layers, the thickness of the cadmium sulfide layer and the dispersion may increase accordingly. To reduce the dispersion, repeated usage of the source material needs to be limited accordingly. Therefore, the utilization rate of the source material is low, normally around 10%.

Problems solved by technology

As cadmium chloride gas is toxic and may cause damages to a human body and cause pollution to the environment, the annealing device is required to have good air tightness.

In addition, corrosive smoke and gas may be produced while cadmium chloride is decomposed under the high temperature.

The above treating methods have complex procedures which may decrease the producing efficiency and also may increase the cost.

Moreover, when preparing a cadmium sulfide film using the conventional CSS method, the utilization rate of the material is low, generally around 10%.

After the crucible is covered, it may be difficult to add the exact amount of the source material into the crucible.

In the repeatedly using process, the particle size, the particles density, and the chemical stoichiometry may change in the sublimation process and they may become difficult to control.

Further, as the CSS method requires vacuum conditions, the device operation needs to be stopped while the source material is added into the device.

Under the same conditions, low utilization rates of the source material will increase the frequency of addition of the source material, which may lead to low production efficiency.

Therefore, the thickness may not be uniform when producing a larger film.

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